Frangible element valve usable in an improved packaging system for a sterilizable calibratable medical device

ABSTRACT

A frangible element valve assembly including a housing having an inlet port and an outlet port connected by a fluid passage that extends through the housing; and an actuator selectively controlling fluid flow through the fluid passage being biased to a predetermined fluid flow control position by a spring member of the valve assembly. Frangible elements of the valve assembly oppose the spring member to temporarily prevent the actuator from assuming the predetermined fluid flow control position, and these elements include breakable members that are broken by an operator to allow the actuator to thereafter assume the predetermined fluid flow control position until selectively changed by the operator.

TECHNICAL FIELD

This invention relates to packages for and methods of packagingsterilizable, calibratable medical devices, and more particularly,provides an improved packaging system for in situ sterilization andcalibration of medical devices comprising hydratable sensor components.

BACKGROUND OF THE INVENTION

U.S. Pat. No. 4,863,016, entitled "Packaging for a SterilizableCalibratable Medical Device", assigned to the assignee of the presentinvention, describes a package for and method of packaging asterilizable calibratable medical device that includes a hydratablesensor component. Because the specification of the above noted patent,including the Background of the Invention, is useful to an understandingof the present invention, the specification of U.S. Pat. No. 4,863,016is hereby incorporated herein by reference.

The medical device referenced in the above noted patent is a bloodchemistry sensor that must be maintained in a sterile environment duringstorage and in a clean environment during the calibration procedure. Thepackaging provided for the medical device accommodates theserequirements. This packaging includes a manifold and a hydrationsolution pouch, each connected to the sensor component by plumbing. Theplumbing also connects the sensor component to the ambient environmentof the plumbing. When the packaging is manufactured, the manifold,plumbing, and medical device are sealed in a wrap including agas-permeable, bacterial retentive surface. The wrap and its contents,including the exterior surfaces of the components, are sterilized byexposure to gaseous ethylene oxide (ETO). During the sterilizationprocedure, the plumbing is adjusted so that the sensor is exposed to theambient environment, i.e., the sterilizing gas. After sterilization, theplumbing is adjusted and the medical device is hydrated within thepackage by directing the hydration solution from the hydration solutionpouch to the sensor by means of the plumbing. To allow storage of thepackage for an extended period of time, a gas-impermeable bag isprovided to define a chamber in which the ambient sterile environment ofthe plumbing is preserved, while the sensor component remains immersedin the hydration solution.

Prior to using the medical device, the sensor component must becalibrated. A portion of the plumbing remote from the sensor componentis removed from the packaging. A reservoir including a calibrationsolution is connected to the plumbing, and the calibration solution isconveyed to the sensor component. As the calibration solution isintroduced to the sensor component, the hydration solution is flushedinto the manifold via the plumbing. In this manner, the sensor componentis calibrated without removing it from the clean environment of thepackaging.

The above description reveals one of the problems with the packagingused for the medical device. Before the sensor component can becalibrated, the hydration solution in which it is stored must be removedfrom the packaging and replaced with the calibration solution. Thisprocess introduces several undesirable complications. It would thereforebe desirable to calibrate the sensor component without removing it fromthe clean environment of the package and without removing the hydrationsolution. The present invention contributes to attaining this objective.

SUMMARY OF THE INVENTION

The present invention provides an improved package for a medical devicethat includes an inner wrap that envelopes the medical device. The innerwrap includes a gas-permeable, bacterial retentive surface. The device,which includes a hydratable sensor, is stored in a chamber definedwithin the inner wrap. Fluid flow into and within the inner wrap iscontrolled by plumbing which is operable to selectively establish,without breaching a portion of the inner wrap surrounding the sensor,fluid communication between the gas-permeable, bacterial retentivesurface and the sensor, to sterilize the sensor and the inner wrap witha gaseous sterilant. Fluid communication is also selectively establishedbetween the chamber and a source of hydration fluid, to hydrate thesensor or between the chamber and an external source of a gas toequilibrate the hydration fluid, thereby to calibrate the sensor withinthe inner wrap.

The present invention is better understood by a consideration of adetailed description in conjunction with the drawings provided herewith.A brief description of the drawings is set forth below.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an exploded isometric view of a package for a medical device;

FIG. 2 is a top perspective view of the packaging tray with an attachedhydration solution pouch;

FIG. 3 is a plan view of the tonometry chamber in the package;

FIG. 3A is a sectional view taken along the lines A--A of FIG. 3, withFIGS. 3B, 3C and 3D being respective top, bottom and side elevations ofFIG. 3;

FIG. 4A is a perspective view, partially in section, of a guillotinevalve used in the package and shown in an open position;

FIG. 4B is the partially closed position of the guillotine valve of FIG.4A;

FIG. 4C is the fully closed position of the valve of FIG. 4A in which asection of the tubing trapped therein is severed;

FIG. 5A is a sectional view of a frangible element valve incorporated inthe package, the valve being built and assembled in a closed position;

FIG. 5B is a view similar to the view of FIG. 5A, wherein the actuatorof the valve is depressed to produce an open position of the valve;

FIG. 5C is an end view of the valve of FIGS. 5A and 5B;

FIG. 5D is a section similar to FIG. 5A, wherein the valve is depressedto break the frangible elements;

FIG. 5E is a view similar to the view of FIG. 5A wherein the valve is inthe normally-closed position following breaking of the frangibleelements;

FIG. 6A is a sectional view of an in-line moisture filter taken alongthe lines 6A--6A of FIG. 2;

FIG. 6B is a sectional view taken along the lines 6B--6B of FIG. 2;

FIG. 7 is a top perspective view showing the packaging tray disposed ina sterilization pouch with a portion thereof visible through a window inthe pouch and further showing a gas permeable Tyvek™ membrane at thewindow area of the sterilization pouch;

FIG. 8 is a top perspective view showing the hydration of the sensorcomponent in the tonometry chamber through the rupturing of thehydration pouch following sterilization;

FIG. 9 is a top perspective view showing the overlapped window and thehydration pouch separated from the main body of the packaging tray, andthe sterilization pouch resealed around the packaging tray; and

FIG. 10 is a representation of the calibration device in block-diagramform.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

With reference to FIG. 1, a preferred embodiment of package 10 includesa packaging tray 12, plumbing 14, a base plate 16 with a peripheralup-turned lip 16a, a gas-permeable, bacterial retentive (Tyvek™) cover18, and an outer wrap 20. As shown in FIG. 2, the tray 12 is molded froma clear plastic material and includes a peripheral flange 12a. The tray12 seats on the base plate 16 and the flange 12a of the tray 12 issecured to the base plate 16 adjacent the lip 16a by a series ofultrasonic welds 17. The tray 12 includes a series of molded-incompartments for holding the various components of the plumbing 14associated with the package 10. For example, a somewhat L-shapedcompartment 21 at the lower left hand corner of the tray 12 as seen inFIG. 2 retains a tonometry chamber 22 in its upright leg 21a. A base leg21b of the compartment 21 provides space for a guillotine valve 23 and afrangible element valve 24.

Above the compartment 21 is a substantially rectangular compartment 25.To the right of compartments 21 and 25 and connected to compartment 25at a common inner side wall 25a is an irregularly-shaped, shallowcompartment 26, whose base wall 29 engages side wall 25a at a mid-planethereof, the compartment 26 having separate niches 26a and 26b at amid-portion thereof, for supporting a delivery device 27 associated witha sensor or sensor component 28 disposed in the tonometry chamber 22. Anelongated rectangular compartment 30 is disposed at the right side ofthe tray 12 for holding a fiber optic connector member 32 associatedwith the sensor component 28. Located in the lower right hand corner ofthe tray 12 is a small, rectangular holding compartment 34 for a purposeto be described below.

The tonometry chamber 22 (FIG. 3) is a small, shallow chamber 22 ofsomewhat ovoid shape, with a flattened outer side walls 22a. A baseplate 22b is bonded to a side wall 22a of the chamber 22. The base plate22b also includes a step portion 22c which extends into the base leg 21bof compartment 21. Receptacles 23a and 24a for retaining the valves 23and 24 are molded into the step portion 22c.

The tonometry chamber 22 also has provided therein a liquid inlet port35, a gas inlet port 36 and a fluid outlet port 37. The volume of thechamber is relatively small, about 8 ml., to minimize calibration time.A baffle 19 is disposed in the chamber 22, somewhat below the center ofthe chamber 22, and between the sensor component 28 and the gas inletport 36. The ovoid shape of the chamber enables a circulatory motion ofthe hydration fluid in the chamber 22 during calibration. Cannula stock(0.012" OD, 0.005" ID) is mounted in the gas inlet port 36 to providetherein a needle-point orifice 36a to enable calibration gases to bubbleinto the tonometry chamber 22. A liquid inlet tube 38 connected to theliquid inlet port 35 of the tonometry chamber 22 is connected at itsopposite end to a hydration pouch 39 carried within a hydrationreservoir 40 disposed externally of the tray 12 and connected thereto bya strap 42 trapped between the tray 12 and the base plate 16. A pouchpopper 44 similar to the one disclosed in U.S. Pat. No. 4,683,0l6 isprovided on the reservoir 40. Interposed between the pouch 39 and theliquid inlet port 35 is the guillotine valve 23 described in detailbelow.

The gas inlet port 36 is connected to tubing 45 which extends to thecompartment 34 to be connected to a hydrophobic filter 46 therein.Provided in compartment 34 are molded brackets 34a, which hold thefilter 46 in place until it is removed and also to retain when it isre-inserted into the tray 12.

At the upper end of the tonometry chamber 22, the fluid outlet port 37receives a guide tube 37a for holding the sensor 28 in the chamber 22.The upper end of the fluid outlet port 37 is connected to a flex fitting49 which extends into the lower end of compartment 25 and is connectedto a fastener 50 which connects the fitting 49 to a bottom wall 25b ofthe compartment 25. The fastener 50 is a fitting which connects thefluid outlet port 37 to a tube 52 which is part of the delivery device27 and extends through compartment 25 and into a channel 54 which isconnected to the upper end of the sensor delivery device compartment 26.

The tubing 52 of the sensor delivery device 27 ends adjacent a Y-fitting55 of the delivery device 27. A side port 56 of the sensor deliverydevice 27, opposite and slightly above the Y-fitting 55, extends towardthe compartment 25. Tubing 57 connects the side port 56 to fitting 58which is connected to a bulkhead fitting 58a disposed in the bottom wall25b of the compartment 25. The fitting 58a in the bottom wall 25b istilted to facilitate access thereto. Tubing 57 extends into compartment25 under the side wall 25a. Tubing 59 connects the other side of fitting58a to one leg of a T-connector 60. Tubing 61 connects the other leg ofthe T-fitting 60 to one side of the frangible element valve 24. Tubing64 connects the other side of the valve 24 to an in-line moisture filteror gas filtration device 65.

The in-line moisture filter 65 is supported in the tray 12 adjacent thecompartment 25. At its upper end the moisture filter 65 is connected bytubing 68 to a fitting 69 which is mounted in an upper wall 25c of thecompartment 25 to vent the output of the in-line moisture filter 65therein. Gas vented from the filter 65 through the fitting 69 tocompartments 25 and 26 passes through the Tyvek™ cover to the ambientatmosphere outside the tray 12. Connecting channel 70 between the sensordelivery device compartment 26 and the connector compartment 30 carriesa cable assembly 72 from the sensor delivery device 27 to the fiberoptic connector member 32. A barrier 71 is provided in the channel 70between the sensor delivery device 27 and the fiber optic connectormember 32. The barrier is an aid to maintaining sterility during thecalibration process and afterward until the package is fully open.

The gas-permeable, bacterial retentive Tyvek™ cover 18 (FIG. 1), whichoverlies an upper face of the tray 12, is partially split, with aleft-hand portion 18a covering the compartment 25 and the sensordelivery device compartment 26 to retain the device 27 therein. Aright-hand portion 18b overlies the compartment 30 for the fiber opticconnector member 32 and the compartment 34 for the filter 46. The cover73 is adhered to the upper face of the tray 12 at its periphery toenclose and retain the sensor delivery device 27, the fiber opticconnector member 32, and the filter 46 within the tray 12. The splitbetween the cover portions 18a,18b is at the separation line 18c, toenable the user to selectively access the fiber optic connector member32 and the filter 46 and its associated tubing during calibration of thesensor component 28.

Disposed between the hydration pouch 39 and the inlet 35 is a guillotinevalve 23 better seen in FIGS. 4A-4C. Tubing 38 between the hydrationpouch 39 and the liquid inlet fitting 35 extends through a channel 90provided on valve body 92 shown partially in section in FIG. 4A. Thevalve body 92 is molded into the base plate 22a of the tonometry chamber22. Slots 93, 94 provided in the valve body 92 receive respectively, aguillotine cutter 95 and a slide clamp 96 attached to an actuator 97 ofthe valve 23. As shown in FIG. 4B, as the actuator 97 descends, theslide clamp 96 in the slot 94 intrudes into the channel 90 to close offthe tubing 38. As shown in FIG. 4C, further descent of the actuator 97causes the guillotine blade 95a associated with the cutter 95 to slicethrough the tubing 38 aligned with the slot 93. In FIG. 4C, it can alsobe seen that escapement barbs 98 engage the respective rear walls 93a,94a of the slots 93, 94 at the end of the downward stroke to hold thevalve assembly 23 closed.

The frangible valve assembly or valve 24 is better seen in FIGS. 5A-5E.The valve assembly 24 includes an outer sleeve 74 having an inletpassage 75 and an outlet passage 76 for conduction of either a fluid ora gas. Rigidly connected to the inner surface of the outer sleeve 74 isan inner sleeve 78 having an annular groove 79 therein. Disposed in theannular groove 79 is one end of a biasing spring 80. Coaxial with theinner sleeve 79 is a valve stem 82, an outer surface of which slidablyextends through a passage 83 formed in the center of the inner sleeve 78for the valve assembly 24. An upper portion of the valve stem 82receives an actuator 84 rigidly mounted thereon to be coaxial with thevalve stem 82. An O-ring seal 85 is placed in a space 85a providedbetween the valve stem 82 and the actuator 84 to assure proper seatingof the O-ring seal 85. An outer end 84a of the actuator 84 includesthree holes 86 disposed at spaced-apart intervals circumferentiallyaround and just inside its perimeter (FIG. 5C). Three tabs 88 areconnected to the inner sleeve 78 by a corresponding number of frangibleelements 89. The tabs 88 align with the holes 86 in the outer end 84a ofthe actuator 84. As shown in FIG. 5A the valve assembly 24 is assembledwith the spring 80 biasing the actuator 84 to the closed position withthe actuator end 84a disposed outwardly from an inner end of each tab88.

As shown in FIG. 5B the actuator outer end 84a is moved downwardly onthe tabs 88 to close the gap shown on the tabs in FIG. 5A and move theactuator 84 downwardly to place the valve assembly 24 in an openposition. With the valve assembly 24 disposed in an open position, theends of the tabs 88 are inserted through the holes 86 in the end 84a ofthe actuator 84. The tabs are then heated and deformed to flatten themand to hold the valve assembly 24 in a normally-open position.Alternative retaining means may also be used. To convert the normallyopen valve assembly 24 of FIG. 5B to a normally closed valve, theactuator 84 is further depressed as shown in FIG. 5D to break thefrangible elements 89. As shown in FIG. 5E, this allows the spring 80 tomove the outer end 84a and the associated actuator 84 outwardly to closethe valve assembly 24 and cause the valve stem 82 to seal off a passagethrough the valve assembly 24. Once the frangible elements 89 have beenbroken, the valve assembly 24 remains closed until the actuator 84 isdepressed by moving the outer end 84a against the biasing spring 80.

The in-line moisture filter 65 is shown in greater detail in FIGS. 6A,6B. FIG. 6A is a cross sectional view taken along the lines 6A-6A inFIG. 2 and FIG. 6B is a longitudinal sectional view taken along thelines 6B--6B of FIG. 2. The in-line moisture filter 65 includes an outerhousing 100 having disposed therein moisture absorbent material 102 thatserves to remove water droplets from air or gas that is passing throughthe filter 65. The moisture absorbent material 102 is held centrallywithin the housing by a plurality of ribs 104, better seen in FIG. 6A,located within the inner diameter of the housing 100. The ribs 104 runlongitudinally along the length of the absorbent material 102. Inoperation, the air or gas passing through the passages created betweenthe ribs 104 and the absorbent material 102 is dried withoutexperiencing a significant pressure drop from one end of the filter 65to the other.

The filter 65 absorbs any overflow of hydration fluid from the tonometrychamber 22 and the plumbing associated therewith and yet is operable topass gases therethrough during ETO sterilization, when the tonometrychamber 22 is vented, as well as when the calibration gases are pumpedinto the tonometry chamber 22. The principal advantage of the filter 65is that the fluid cannot slosh out when the tray 12 is moved. Next, gasvents through the Tyvek™ cover 18, which also acts as a bacterialbarrier to ingress of organisms back down the vent once calibration isover. The outer housing 100 is clear, to enable viewing of the absorbentmaterial 102 therein. The absorbent material is colored, and changescolors when wet, to indicate the presence of moisture. Also, thepresence of moisture in the filter 65 assists in maintaining the fluidlevel in the tonometry chamber 22 during storage.

The sterilization process is separate from the hydration process and isbest understood by a consideration of FIG. 7. In FIG. 6, the tray 12 isinserted into a pouch or outer wrap 20 which is comprised mostly of foilbut includes a clear window 110 and a gas-permeable, bacterial retentivestrip 112. The pouch 20 is fully sealed on three sides and after thetray 12 is inserted therein, is sealed on the fourth side as shown at114. With the tray 12 sealed in the pouch 20 as shown in FIG. 6, valves23 and 24 are fully open. The hydration pouch 39 is gas-impermeable.With the pouch 20 sealed and the tray 12 in place, the tray 12 is thensubjected to ETO sterilization, with the ETO gas flowing into the tray12 through the gas-permeable, bacterial retentive strip 112. During ETOsterilization, in which the ETO gas is introduced through the gaspermeable, bacterial retentive (Tyvek™) strip 112 in the outer wrap 20and through the Tyvek™ cover 18 on the packaging tray 12, the tonometrychamber 22 and the plumbing associated therewith is open to thesterilization gases to sterilize the chamber 22, the tubing, the valves23 and 24, the delivery device 27, the exterior of pouch 39, thereservoir 40, the pouch-popper 44 and the tubing sections 38 and 45respectively associated with the delivery of hydration fluid and withthe delivery of calibration gases into the tonometry chamber 22.

When the ETO sterilization procedure is complete and the gassesassociated with ETO sterilization have dissipated or have been drivenoff from the tray 12 and the pouch 20, the hydration procedure isinitiated as shown in FIG. 8. Valves 23 and 24 remain fully open and thehydration procedure is conducted within the sealed pouch 20 as shown inthe visible portion thereof at the left side of FIG. 8. Pouch popper 44is activated to rupture the hydration pouch 39 spilling the hydrationfluid into the reservoir 40. The pouch is then squeezed until thehydration fluid is forced through the tubing 38, through the guillotinevalve 23, and into the tonometry chamber 22.

The air in the tonometry chamber 22 is vented out through the upperfluid outlet fitting 37 and the tubing 52 through the compartment 26associated with the sensor delivery device 27 as well as the side port56. Excess fluid is conducted through the side port 56, through tubing59, through the frangible valve 24 and into the in-line moisture filter65. Excess fluid from the tonometry chamber 22 may also flow out throughthe gas inlet valve 36 through tubing 45 to the fitting 46. However, thehydrophobic filter 46 prevents fluid from flowing therethrough. Fluid isalso present in the T-fitting 60 and is stopped by a hydroprobic filter60a. The filter 65 also traps excess moisture in the absorbent material102 provided therein.

Once the hydration of the sensor component 28 in the tonometry chamber22 is complete, the guillotine valve 23 is actuated as shown in FIGS.4A-4C to first close the tubing 38 and then to cut it to prevent furtherinput of hydration fluid to the tonometry chamber 22. Then the frangibleelement valve 24 is first pushed to break the frangible elements 89,then released to close the valve 24 to prevent the loss of hydrationfluid from the tonometry chamber 22. The guillotine valve 23 is operatedthrough the pouch to maintain sterility of the tray 12 during hydration.The user is able to separate the hydration pouch 39 from the packagingtray 12 and simultaneously close the tonometry chamber 22 withoutdamaging the integrity of the sterilization pouch 20 in which thepackaging tray 12 is sealed.

Furthermore, the hydration pouch 39 and the gas permeable, bacterialretentive portion 112 of the sterilization pouch 20 can be separatedfrom the packaging tray 12 to enable the fully hydrated sensor 28 to besealed in a more compact, gas-impermeable sterilized pouch until it isready for use. The "spent" hydration pouch 39 is unsightly and possiblyconfusing to the user.

The frangible element valve 24 enables the free flow of gas throughoutthe plumbing during the sterilization process, and the hydrationprocess, and thereafter the frangible elements 89 are broken to producea normally-closed, push-to-open valve 24 which seals the gas inlet 36 ofthe tonometry chamber 22. The valve 24 is also operated through thepouch 20. The valves 23 and 24 are also recessed within the tray 12 toprevent inadvertent operation.

With tubing 38 cut, and both valves 23 and 24 closed, the tray 12holding a fully hydrated sensor component 28 can be resealed as shown inFIG. 9. The strap holding the reservoir 40 to the tray 12 is merelytrapped between the tray 12 and the bottom plate 16. Therefore, with thetubing 38 cut, the reservoir 40 and the pouch 39 therein can beseparated from the tray 12 to be disposed in the clear window 110 of thepouch 20 with the gas permeable, bacterial retentive Tyvek™ strip 112.Thereafter, that portion of the pouch 20 can be cut away as shown inFIG. 8 and the pouch 20 resealed as at 116 to seal the tray 12 in acontrolled sterile atmosphere impervious to gases and which also blocksout light. Although the clear window is useful during the in-pouchhydration step, the elimination of window 110 immediately thereafter, asshown herein, markedly increases storage times for the tray 12 and itsassociated sensor 28.

To calibrate the sensor component 28, the sterile tray 12 is removedfrom the sealed pouch of FIG. 9. The right-hand side 18b of the Tyvek™cover 18, partially split at 18c in FIG. 1, is removed to permit accessto the fiber optic connector member 32 and the gas filter 46. Theleft-side 18a stays in place and, in cooperation with the sterilebarrier 71, maintains the compartments 25 and 26, as well as the sensordelivery device 27 and the filter 65 in a sterile environment duringcalibration. The filter 46 is connected to a calibration device 120(FIG. 10) to permit the infusion of gases containing the known analytesinto the hydration fluid. Components of the calibration device 120engage the tonometry chamber 22, first to open the valve 24 to permitthe flow of calibration gases into the chamber 22, then to control thetemperature of the hydration fluid in the tonometry chamber 22 duringthe calibration process.

The tonometry chamber 22 is designed as a gas-driven, circulating loop.The needle orifice 36a bubbles the calibration gases into the chamber22, with the baffle 19 provided in the middle of the chamber 22enhancing circulatory motion of the hydration fluid around the baffle19, and also preventing the bubbles generated in the hydration fluidthrough the needle orifice 36a from impinging on the sensor component28, thus to minimize the erratic response thereof during calibration.The baffle 19 also permits a reduction in chamber volume by taking upbuffer volume. The turbulence generated by the circulating loop alsopromotes better mixing of the liquid with the gas, thus to decrease thetime needed for gas equilibration. Mixing is also necessary for uniformheating, i.e., temperature control.

The gas pressure in the chamber 22 creates a movement of fluid out ofthe filled calibration chamber 22 at first, leaving behind an optimumamount of fluid for fast mixing. Fluid and gas does not mix well in afilled chamber. Also, the level of the fluid must remain above the levelof the internal baffle 19 to maximize the mixing action. As fluid movesout of the chamber 22, the fluid level drops from 50 mm (filled) to 30mm in less than ten seconds, and stays at the lower level for theremainder of the calibration. The excess fluid is absorbed by the filter65. The amount of fluid remaining in the chamber is controlled by theheight and geometry of the gas outlet port 37.

The connector member 32 is also connected to the calibration device 120to compare the readouts during equilibration of the hydration fluid tothe known valves of the analytes used for calibration. For convenience,the compartment 30 holding the member 32 during storage is also sized tohold an optical receptacle (not shown) of the calibration device 120during calibration.

The packaging technique of the present invention allows a blood gascatheter to be calibrated immediately prior to use without the need of ablood gas analyzer to obtain reference calibrant values. The calibrationtechnique is practical and allows calibration using aseptic handlingthat protects the cleanliness of the medical device and minimizes thepossibility of contamination of the sensor component.

Having defined a preferred embodiment of the invention it should beunderstood that other embodiments are possible. The configuration of thesensor component of a specific device may dictate alternativeconfigurations for the packaging.

I claim:
 1. A valve assembly comprising:a housing having an inlet portand an outlet port connected by a fluid passage that extends through thehousing; an inner sleeve rigidly connected to the housing, and having acentral passage therethrough; an actuator coaxial with the inner sleeveand having an outer surface slidably extending through the passageformed in the center of the inner sleeve; first means for biasing theactuator to a normally-closed position for the valve assembly in whichfluid communication between the inlet and outlet ports is interrupted;second means for retaining the actuator against the bias of said firstmeans in a normally-open position for the valve assembly in which fluidcommunication is achieved between the inlet and outlet ports, the secondretaining means including an actuator outer end having a plurality ofholes disposed therein at spaced-apart intervals and circumferentiallyaround and just inside the perimeter thereof, and a correspondingplurality of tabs each connected to the inner sleeve by a respectivefrangible element, the tabs on the inner sleeve to align with the holesin the outer end of the actuator, and movement of the actuator on thetabs driving the valve assembly to an open position and thereafterdeforming the ends of the tabs retains the valve assembly in anormally-open position; the tabs being frangible to enable the firstmeans to bias the actuator to the normally-closed position when thesecond means is broken.
 2. A valve assembly as claimed in claim 1wherein said first biasing means includes an annular groove provided inthe inner sleeve, and a spring having opposite ends, with one end of thespring disposed in said annular groove and an opposite end bearingagainst the actuator to bias it to the normally-closed position.